Cotoneaster Plant Named &#39;Emerald Sprite&#39;

ABSTRACT

‘Emerald Sprite’ is a new Cotoneaster cultivar with a highly compact, mounding habit, extremely dense foliage, short internodes, and improved fire blight resistance.

Botanical denomination: Cotoneaster x suecicus.

Variety designation: ‘OSUCOT1’.

BACKGROUND

The present invention relates to a new and distinct cultivar ofCotoneaster plant, botanically known as Cotoneaster x suecicus andhereinafter referred to as ‘OSUCOT1’.

The new Cotoneaster plant is a result of a breeding program directed bythe inventor to develop new cultivars of cotoneasters that are resistantto fire blight caused by the pathogen Erwinia amylovora, are compact,and perform well in nursery production and landscapes.

‘OSUCOT1’ originated as an open-pollinated seedling collected fromCotoneaster x suecicus ‘Coral Beauty’ (seed parent, unpatented) during2011 that was pollinated by an unknown pollen parent. It was originallyaccessioned and evaluated as H2011-02-001. ‘OSUCOT1’ was grown incontainers during 2012 for observation and selected for propagation in2013. It was propagated by stem cuttings that rooted easily with hormonetreatment under mist. Clones produced from serial asexual propagationhave demonstrated the stability of its traits from 2013 through 2018.The original plant was left outside unprotected in a #3 container duringwinter 2013-14 and was killed during temperatures that reached 0° F.Replicates produced from stem cuttings were included in a glasshousestudy to evaluate fire blight resistance of hybrids and parents during2014. Plants were inoculated on Apr. 28, 2014 with a virulent strain(Ea153) of Erwinia amylovora by bisecting the two youngest leaves onvigorously growing shoots according to Rothleutner et al. (2014). Noneof the plants of this accession exhibited disease symptoms (0% shootinfection). ‘Coral Beauty’ had 11.1% mean shoot infection during thatevaluation.

SUMMARY

Plants of the new Cotoneaster have not been observed under all possibleenvironmental conditions. The phenotype may vary somewhat withvariations in environment and cultural practices such as temperature andlight intensity without any variance in genotype.

The following traits have been repeatedly observed and are determined tobe unique to ‘OSUCOT1’. Collectively, these traits distinguish ‘OSUCOT1’from other available cotoneasters.

-   -   1. Highly compact growth form with a clumping growth habit, as        opposed to the more standard creeping habit.    -   2. Resistance to fire blight.    -   3. Extremely glossy, dark green leaves adaxially.    -   4. Excellent container production performance.    -   5. Short internodes.    -   6. More vigorous and faster production than other dwarf        cultivars such as ‘Tom Thumb’ (unpatented).

Compared to its female parent, Cotoneaster x suecicus ‘Coral Beauty’,plants of ‘OSUCOT1’ are easily distinguishable based on the followingtraits:

-   -   1. ‘OSUCOT1’ has a more regular growth form.    -   2. ‘OSUCOT1’ has a more compact habit.    -   3. ‘OSUCOT1’ has fire blight resistance.    -   4. ‘OSUCOT1’ requires little or no pruning during production to        yield salable plants.

The foregoing and other objects and features of the new variety willbecome more apparent from the following detailed description, whichproceeds with reference to the accompanying figures.

BRIEF DESCRIPTION OF THE DRAWINGS

The accompanying photographs illustrate the new ‘OSUCOT1’ cultivar incolor as nearly true as it is reasonably possible to make the same incolor illustrations of this nature. The plants were grown outside infull sun in containers and in the landscape in Corvallis, Oreg., USA.

FIG. 1—Illustrates a typical mature four-year old plant growing in acontainer. The mounding habit is clearly visible. The scale included is92 cm tall, which helps illustrate the compact nature of ‘OSUCOT 1’.

FIG. 2—Illustrates the uniform nature of clones produced from stemcuttings. Presented are two groups propagated at different times. Anolder group (left) and younger group (right) clearly both exhibit thecharacteristic mounding, compact habit.

FIG. 3—Illustrates the consistent performance in the landscape where itmaintains its mounding habit and moderate to heavy production of flowersthat are pink in bud and open to white.

FIG. 4—Illustrates the attractive pink floral buds prior to opening.

FIG. 5—Illustrates the near-pure white flowers.

FIG. 6—Illustrates the approximate color of fruit.

FIG. 7—Illustrates the glossy leaves as well as color of new foliage andstems.

DETAILED DESCRIPTION

The following is a detailed description while observing mature plants ofthe new cultivar following the rooting of stem cuttings. Such plantsranged between two and five years of age and were found to haveconsistent morphology with the exception of size (younger plants aresmaller). Plants were observed growing outdoors in full sun inCorvallis, Oreg., USA. Color terminology is in accordance to The R.H.S.Colour Chart (fifth edition) of The Royal Horticultural Society, London,2007.

-   Classification:    -   -   Botanical name.—Cotoneaster x suecicus.        -   Common name.—Cotoneaster.-   Parentage: Open-pollinated seedling collected from Cotoneaster x    suecicus ‘Coral Beauty’, which was pollinated by an unknown pollen    parent — likely a self-pollination.-   Plant description:    -   -   Growth habit.—Cushion-like, low growing with somewhat            upright stems.        -   Height at maturity.—31 cm.        -   Width at maturity.—74 cm.-   Stem:    -   -   Mature stem texture.—            .        -   Mature stem color.—Greyed-Brown Group 199B.        -   Immature stem color.—Greyed-Purple Group 183A.-   Leaves:    -   -   Type.—Evergreen to semi-evergreen.        -   Arrangement.—Alternate.        -   Shape.—Elliptic, keeled.        -   Veins.—Pinnate.        -   Mature leaf texture.—Glabrous adaxially, light pubescent and            reticulate abaxially.        -   Base.—Cuneate to nearly rounded.        -   Apex.—Retuse.        -   Margin.—Entire.        -   Mature leaf size.—1.7 cm long×0.8 cm wide.        -   Immature leaf color.—Greyed-Purple Group 183A.        -   Immature stem color.—Greyed-Purple Group 183A.        -   Mature leaf color.—Adaxial surface — Green Group N134A,            Abaxial surface — Green Group 138B.        -   Petiole length.—0.4 cm.-   Inflorescence:    -   -   Number of flowers per inflorescence.—Solitary or 2-5.        -   Diameter.—0.8 to 1.1 cm.        -   Type.—Solitary or corymb.        -   Flowering season.—May to June.        -   Bud.—Red-Purple Group 68A to N57A.        -   Petal.—Five petals, White Group NN155C.-   Fruit/seed:    -   -   Fruit.—Generally obovate, 0.5 cm diameter and 0.5 cm long,            base color is Greyed-Red Group 180C with a somewhat            irregular coloration and generally lighter than other            cultivars with green undertones.-   Propagation and production: 2.5 cm softwood tip cuttings treated    with 1000 ppm auxin and set in 3 parts perlite : 1 part peat in a    community flat under intermittent mist and bottom heat rooted 90% in    28 days. ‘OSUCOT1’ plants were put through a production schedule    that indicates plants can be propagated and produce a finished trade    gallon container in approximately 9-months.-   Disease and insect resistance: 0% shoot infection following    inoculation with a virulent strain of Erwinia amylovora (Ea153),    whereas its seed parent, Cotoneaster x suecicus ‘Coral Beauty’ had    11.1% mean shoot infection during the same evaluation.

I claim:
 1. A new and distinct cultivar of Cotoneaster plant asillustrated and described.